Their first China flights since February took off from Dallas on was headed to Shanghai earlier this year.

Travel was halted between the world's two largest economies due to the global health crisis.

But in recent months the U.

S government has been pushing for more air services to China.

A US China agreement allows them to operate more than 100 weekly flights between the two countries.

In September, the U.

S State Department eased a travel advisory for Americans considering going to China or Hong Kong.

It was changed from do not travel to reconsider travel, citing improved conditions.

But China has some of the most strict entry requirements of any country in the world.

As of last week, U.

S travelers must take a new cleric acid test and a blood test for antibodies against the coronavirus no more than 48 hours before boarding.